BOOKS AND CURRENT LITERATURE 



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physiological laboratorj-. But do we realize that what we discover and 

 demonstrate on a very minute, and it should be admitted, on a very 

 inexact, scale in laboratory and experiment house, takes place on a 

 great scale out of doors in every growing season? Ganong realizes this 

 and tries to demonstrate it to others, less wholesomely familiar with the 

 woods and fields. 



Then follow chapters on cross-pollination, dissemination, plant breed- 

 ing, classification, and evolution. These subjects are treated from the 

 usual standpoint but with unusual charm. One cannot help regretting 

 the perpetuation of the idea of "mimicry" in books about plants, 

 whatever may be said about its occurrence in zoological literature; for 

 unless one concedes consciousness to plants, can one admit that they 

 mimic? This, however, is but a minor fault, only too easy for natural- 

 ists after the generations of training to which they have been subjected. 



One word of protest should be uttered against the publisher, who 

 has so loaded a readable book with heavj^ clay paper that it is most 

 inconvenient unless supported by something more stable than the hand. 

 — G. J. P. 



Toxicity of Salts. — Publications have appeared from time to time 

 in support of the idea that very small quantities of certain inorganic 

 salts in solution are either extremely toxic to plant growth or may 

 act as a stimulant. The present paper^ includes, in the form of a 

 preliminary report, a series of investigations upon the tolerance of 

 wheat and vetch to the presence of copper sulphate, zinc sulphate, 

 manganese sulphate and sulphuric acid. It is concluded from this 

 work that the tolerance of plants for certain of the inorganic salts, 

 commonly regarded as very poisonous, is much greater than we have 

 been wont to believe and moreover that they do not merely tolerate 

 them but are actually stimulated by quite considerable quantities of 

 the toxic salts. One is not at all surprised at these conclusions when 

 he notes that a sandy soil to which had been added a good supply of 

 humus, was used in which to grow the plants. This would render it 

 impossible to even guess at the number of unknown factors under the 

 names of absorption phenomena and chemical reactions between the 

 salts added and those already present in the soil, which would enter 

 into the interpretation of results. — Frederick A. Wolf. 



•Lipman, C. B. and Wilson, F. H., Toxic inorganic salts and acids as aflfecting 

 plant growth. Bot. Gaz. 55 : 409-420. 1913. 



